I have checked the shop you shared and it seems to me that said shop has their own, custom bundling solution.
They most likely managed to create it by hiring a Shopify Expert. You could do the same, but hiring an expert will cost you some money.
You could also try out an alternative, such as the Bundler - Product Bundles app (https://apps.shopify.com/bundler-product-bundles),,) which comes with a free plan and work with the Seal Subscriptions app. This means that you will be able to offer custom bundles to your customers with the subscription option integrated in it. However, the widget will most likely look different from the shop you shared